1. AIDS Reference Laboratory, Centre Hospitalier Universitaire St Pierre, Brussels, Belgium
2. HIV/STD Reference Laboratory, Clinical Virology Unit, Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
3. AIDS Reference Laboratory, Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
4. AIDS Reference Laboratory, Université Libre de Bruxelles, Brussels, Belgium
5. AIDS Reference Laboratory, Katholieke Universiteit Leuven, University Hospitals Leuven, Leuven, Belgium
6. AIDS Reference Laboratory, Medical Microbiology Unit, Université Catholique de Louvain, Brussels, Belgium
7. AIDS Reference Laboratory, Centre Hospitalier Universitaire de Liège, Liège, Belgium
8. AIDS Reference Laboratory, Vrije Universiteit Brussel, Brussels, Belgium
9. Laboratory of Clinical and Epidemiological Virology, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Katholieke Universiteit Leuven, Leuven, Belgium